Method of producing laminæ for transformer-cores.



PATENTED FEB. 12

W. A. HALL. METHOD OF PRODUCING LAMINJE FOR TRANSFORMER GORES.

APPLICATION FILED MAR.5. 1901.

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PATENTED FEB. 12, 1907.

W. A. HALL. METHOD OF PRODUCING LAMINE FOR TRANSFORMER GORES.

APPLICATION FILED MAR. 5.1901.

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Inventor.

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UNITED STATES PATENT CEEICE,

WALTER ATWooD HALL, OF LYNN, MASSACHUSETTS, ASSIGNOR To GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YCEK.

METHOD OF PRODUCING LAWN/E FOR TRANsFoRMER-coREs.

Specification of Letters Patent. Application filed llfarch 5, 1901. Serial No. 49,6 94.

Patented Feb. 12, 1907.

setts, have invented certain new and useful Improvements in Methods of Producing Laminae for Transformer-Cores, of which the following is a specification.

- This invention relates in general to new and useful improvements in the construction of laminated transformer-cores of the eneral type disclosed in the patent to Moo y, No. 567,250.

The invention relates specifically to a new and useful method in manufacturing corelaminae of the special design required for the transformer of Augustine R. Everest, set forth in application for Patent, Serial No. 49,693. 1

As described in the patent to Moody, the coils were wound on two bundles of straight laminae having tongueand-groove ends, which bundles were then placed a suitable distance apart and their ends, joined by short bundles of laminae to complete the magnetic circuit. One end of each short bundle interlocked with the tongue-andgroove end of the long bundle which consti- The other end of each short bundle abutted against the side of the long bundle which constituted the other leg of1the core. This proved a very cheap and convenient mode of constructing a durable and eflicient transformer. Avery important feature was the economy in producing laminae. However, there was a not inconsiderable core loss in transformers constructed' in the above improvement, which is due to the fact that there were necessarily four joints between the laminae. With the aid of and in accordance with the invention of Everest transformers have been made which Show a reduction in core loss of over the Everest transformer, whereby a very considerable saving of material, amounting to at least ten per cent, is effected in their manufacture'without in any wise sacrificing 5 5 the advanta es obtained by the invention of Everest, an whereby a susbstantial saving in the cost of labor is effected in that an increased number of laminae are produced by a single operation.

The core made in accordance with this invention is built up of substantially U-shaped laminae, each of which has a long and short; leg, the difference between the lengths of the legs being substantially equal to the width of the bases of the laminae, as it has been found thatlaminae or sheet metal punchin s of, this shape can be economically produce at a much reduced cost for labor and with very little waste of material while retaining the advantages of the small number of joints and the decreased core loss which were made possible by the U shaped punching. v

Figure 1 is a plan of a sheet-metal blank upon which is performed the first or punching operation. Fig. 2 shows a short .end laminae which is the result of this operation. Fig. 3 is a plan which shows the result of a second or shearing and final operation. Fig. '4. is a reversed plan of the blank shown in Fig. 1' before the punching operation has '5 includes .views of the taken .place.

are punched or sheared Figl. three parts whic from the blank shown in Fig. 4, and 6 is a perspective view showing the core in process of constructlon from the parts shown in Fig. 5.

Wi h reference to l the first or unchin operation, which is accomplished by a suitable die, trims away the edges X Y of the sheet-metal blankA, punches the pin-holes H, and punches the holes E and F, leaving the strip M- between them. The sheet of laminae E (shown in Fig. 2) occupies the space E and is cut out in this operation in order to save a separate 0 eration of cuttingit to preper length later, t e length shown in i Fig. 2 being its final len th for adapting it to be used as an end sheet For the core. During the first operation also the guide G is cut in the upper portion of the blank A. The part M is left ,to hold the parts rigid until the sec 0nd or shearing o eration, when, as is clear, it can also be s eared off. The part .F, which is wasted, is punched out in order to permit the second operation to be merely. a

shearing operation without the punching,

which would be necessary if the corners were not removed before the second operation. The removal of the part E by punching permits'the shearing to be accomplished along the dotted line at the lower portion of Fig. 1-. In any case there must be a free space at the beginning of the part to be s ieared in order to permit the operation of the shear. The second or shearing operation results in the separation of the metal along the dotted lines in Fig. 1, the result of which is seen in Fig. 3, wherein the guide I of the lower right-hand corner is also formedf The punching and shearing operations are conducted substantially simultaneously, and

therefore at one complete operation are produced two U-shaped punchings and one end punching, whereas it has hitherto been considered impossible to produce in one operation more than one straight-leg punching and one end punching. As one U-sha ed punching is equivalent to two straight egs and one end, it-is clear that I produce in one operation four times as many le =s and three times as many end pieces than hitherto has been possible. In the case shown the part M v is wasted; but this'is not always the case.

form a rectangular figure.

Even when the part- M is wasted, this is practically all the waste there is, whereas hitherto it has been considered necessary to waste three-eighths of an inch entirely around each punching. Furthermore, as it has been considered necessary to allow three-eighths of an inch of waste'in the Width of the center of the blank, by my invention only it is possible to obtain the punching E from .the center of the blank. In 3 it will be seen that two substantially U-shaped laminae are formed, each having a long and a short leg, the length of the latter of which is equal to the difference between the length of the long leg and the width of the base of the U-shaped laminae, so that when the-parts are arranged, as in Fig 3, just as'they come from the blank A they In addition it will 'be observed in Fi 3 that the space between the short inner Io I same width as the legs or bases of the U- shaped laminae, or, in other words, the distance betweenthe long leg and the short leg, of one laminae is twice the width of either leg and therefore equal to the added widths of both he From themetal in the (space between t e short legs B and C in Fig. 3 the end sheets of the core are always formed, and according to the dimensions of any given transformer there will be a greater or less waste. of metal wasted in the construction of this transformer is represented by M and F. H the transformer which is be' built is of sufficient size, the material M (t e part F being as small as possible) may serve for cores of smaller transformers. On the other hand,

the core may be so proportioned that the gsB and C is of the In the case illustrated the amount metal taken from theentire space E M may be used as the end sheet for that particular transformer. In- Fi 5' the three pieces formed from the blan are shown separately and it should be particularly noted that the lamina O has the outside corner of its longer leg C cut away at I, while the lamina B has the inner corner of the end of its long leg B cut away at G. In Fig. 6 is shown a artial assemblageof these parts, held together by wooden pins W, which fit tightly in the holes The guide I on the right-hand corner of they end of the-right-hand long leg'and the guide G on the left-hand corner of the-end of the long leg behind the first serve to indicate to the operator that the end sheet E is to be placed in the space between them. The other end of the end sheet abuts against the side of the end of the long leg which is contained in the left-hand leg of the core. The end of the next end sheet is inserted between the roject-ing ends of the long 1 of the leftand core-leg, as indicated to t e operas tor by the guides I and G, and thisvend sheet abuts against the inner side of the end of the apposite long leg of the right-hand core-leg. he remaining end sheets alternate in the same way until the core is completely assembled.

In practice, as shown in the drawings, the units of assemblage comprise two or more single laminae.

.Further reference to Fig.6 is necessary in order to explain how from the two different kinds of U-shaped laminae shown in 5 the result shown in 6-is accomplished by 7 means of the alternating guides I and G. Beginning at the bottom of Fig. 6 a group of two laminae C is laid with its short leg C in the foreground and its long leg C, with the outer cut-away corner I, in the background. Upon thisgroup is laid a group of two laminae B, with their long legs B and innercut away corner G in the foreground and their shorter legs 13 in the bac ound. third layeris a group of two-of t esame laminae B which constitute the second layer, but turned'upside down, so that their short legs B are in the foreground and their longlegs B and inner cut-away corner G are in the background. The fourth layer consists of a oup of two ofthe laminae C which form the ist layer, but turned upside down, so that their long legs 0 and outer cut-away corner I are in the foreground and their short legs C are in the background. This series of four layers is continued until the 1 core is completely assembled. From this description it 5 ollows that the successive projecting long legs have their cut-away portions-located alternately on the inside and outside of the core-leg, so that the operator can quickly and accurately insert the ends E in vthe proper position after the coils have been slipped over the core-legs.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. The method of producing from sheet I 5 metal, U-shaped laminae having the space between their legs equal to twice the width of one leg, the difference between the lengths of the legs being equal to one-half the distance between them, which consists in punching a portion out of the sheet to provide a free space in front of a portion to be sheared, and

t en in conducting the shearing'operation,

beginning at the edge of the free space pre- \pared by the punching operation, whereby the extra strip remaining isof the same width as the legs of the U-shaped laminae.

2. The method of preparingtransformer core-pieces consisting of U-shaped portions and straight portions from strips of sheet 0 metal which consists in punching a straight portion from between the interleaved legs of a pair of U-shapedportions and adjacent the end piece of one of the U-shaped portions,

and unching a waste portion from the ma- 3 5 teria between the'interleaved legs of the U- shaped portions adjacent the end piece of the other U-shaped portion and then separating the U-shaped ortions by shearing.

3. The met od of preparing transformer 0 core-pieces consisting of U-shaped portions from plates of sheet metal, which consists in punching out of the plate, a portion of the material between the interleaved legs of the U-shaped portions adjacent the end piece of each U-shaped portion and then separating the U-shaped portions by shearing cuts.

4. The method of preparing from strips of sheet metal transformer-lammae composed of- U-shaped portions and straight end-closed 5o portions, the legs of each U-shaped portion being separated by a space double the width of a leg, which consists in punching out the material from between the interlocked le s of a pair ofU-shaped portions, one of sai U- shaped portions "being reversed with respect 4 to the other, and then separating the U- shaped portions by shearing, the portion punched opt being of length to form the endclosing piece and its removal leaving a free space from which a shearing cut may start.

5. The method of simultaneously producing a pair of U-shaped laminae from a plate of sheet metal which consists in punching out of the plate a portion of material to form a space between the interlocked legs of the laminae, then completing the shaping of the laminae by shearin cuts, some of which start from the space eft by. the punching.

6. The method of preparing transformer core-pieces consisting of U-shaped portions, 76 one leg of which is longer than the other by the width of the yoke 01' base connectingthe legs, and straight end-closingportions, which consists in punching a straight portion from a strip of sheet metal of a width equal to the 7 5 length of a long leg of a U-shaped portion plus the width of the connectin base portion thereof, so that the hole forme which extends transversely to the length of the strip is separated from one side of the strip So by a distance equal to its width and from the end of the'strip by a distance equal to twice its width, punching another portion of material irom the strip so that the hole left is in, line with the first-mentioned hole and of the same Width and is separated from the oppo-' site side of the strip by a distance equal to the width ofsaid base and then separatin from the strip by shearing cuts two U-s aped laminae of the form described, the outer edge of the base of one of which is one side edge of the strip and the outer edge of the base of the other is the other side edge of the strip, the inner edges of the interlocked inner legs of the U-shaped punchings being in line with the 4 edges of and separated by said holes.

7. The method of preparing from a strip of sheet metal transformer core parts consisting of U-shaped portions and straight endclosing portions, each of which is of a width I equal to the width ofeach leg of the U-shaped portions, the legs of each U-shaped portion being separated by a space double the width .of a leg, which consists in punching out of the strip an end-closing portion and a Waste por-' tion in line therewith, and then shearing from the strip two U-shaped portions, parts of the inner edge s'urfac'e of one leg of each of said U-shaped portions being formed by said punching-out operation. ,7 y In witness whereof I have hereunto set my hand this23d day of February, 1901. v

' WALTER ATWOOD HALL. Witnesses: i

DUGALD MoK. MoKILLoP, HENRY OVWESTENDARIP. 

